Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden and does well: it discloses async behavior (returns job_id immediately, poll get_job), the ~10s output length, that text is never baked in, and that project_name is only applied in post when ffmpeg is available — implying graceful degradation. It omits cost/rate-limit implications and what happens on a failed render job.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with the deliverable and its constraints, then tier guidance, then the async/return contract, then the music alternative. No sentence is redundant with another.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description supplies the essential return contract (job_id + poll get_job) and the asset characteristics an agent needs to build a prompt. It leaves cost/balance considerations to the sibling pricing tools, which is reasonable, but the absence of any failure-mode note keeps it just short of complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 50%, and the description compensates for both undocumented parameters: it explains that project_name is a post-production overlay applied only when ffmpeg exists, and that tier=budget maps to MiniMax Turbo. The two schema-documented params (prompt, owns_rights) need no further help.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence names a specific verb ('Generate'), the exact asset ('~10 second launch teaser'), and two defining constraints ('original', 'no baked-in text') that separate it from generate_banner and generate_image. It also names the sibling that handles the adjacent asset (music via generate_launch_kit).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit guidance on the tier choice ('Use tier=budget for MiniMax Turbo'), the next action after calling ('poll get_job'), and where to get music instead ('separate tool or mixed in generate_launch_kit'). It does not state when to prefer this tool over generate_image or generate_banner for a launch asset, so it stops short of a full routing rule.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.